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Oddly similar recall when the ‘22 125/150s were eating rod bearings.
Crazy 😳
What is wrong with these motors?!
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Looks like a conrod failure, snapped at small end, sending piston into head.
Cheap Asian made components...
I’ve seen a lot of 2-stroke failures, but I’ve never seen anything like this - that head 😬
I’d be worried about catching shrapnel from a failure like that.
I have one of these bikes (2023 MC 250) that's jetted and running great on VP T2 (40:1). I've had no problems other than the finicky Mikuni carb needing the gasket rebuild kit, but I've been following this thread for the past year and the fact that the stories keep coming is concerning. I love this bike but I'm worried it's a ticking time bomb.
What would the proactive solution even be here? Preemptively replacing the conrod and top end with something other than OEM? I would prefer not to have my bike detonate off a jump face. I'd e-mail KTM/Pierer/GG but I am entirely confident that would provide no useful information.
KTM/Pierer/GG have bigger issues, like trying to avoid bankruptcy!
Like Honda, Yamaha, Kawasaki and Suzuki?
Exactly lol.
Yes, put either a Pro-X or Wossner rod in and a Wossner forged piston if you want a little more assurance.
jG791,
The fix is to have the crank sent off to have a prox or wossner rod installed. Brian Lambert at Mototech does a great job and is very affordable. He can do anything and I highly recommend. He gets brand new bikes like this and changes the rod out and better piston before bikes are even ridden. He did mention that he has seen a lot blow up under 20 hours but said if it lasts longer its usually ok for the most part. I wrench on the side so tearing down motors are not a problem. I take care of a lot of buddies in NorCal which helps as dealers are so expensive.
MPmotors_MX
FGR01 & MikePierce244,
Thank you both, I'll look into this.
Crank Works is also very good, I've used them a number of times over the years. Premium Crankshaft Products and Services - Crank Works
My two strokes get wössner rods, my fourstrokes get pankl or carillo.
I don’t send mine off, I do them myself.
Life got in the way and I've been riding other bikes, so out of an abundance of caution, my GasGas 250 sat unused in the garage for 6 months. Doing a teardown to have a new Pro-X rod put on (along with a TSP head), I noticed a lot of wear on the small end. You might not be able to tell in the pic, but the small end isn't just worn, there is a significant height difference in the material - it's chewed away like I took a belt sander to it.
This bike only has 5.7 hours. Run on a Mikuni + 40:1 VP T2, stock head/piston/etc., no crazy mods. Used only for moto 5-10 times, definitely not at a ridiculous pace since the bike isn't even broken in yet.
I e-mailed an engine guy here in Kentucky for his thoughts (since I'm not an expert), who said this rod design, with the cutout on the small end, was a design KTM/GG switched to some years back, and which created small end issues on KTM bikes when they were essentially unheard of before. The problems are created due to the loss in load-bearing surface. Interestingly, the Pro-X rod does not have the cutaway; his recommendation was installing the Pro-X rod, as others have stated here.
Just adding another data point in case anyone finds it helpful.
Pit Row
Wow. I can’t imagine the reason for the cutout in the small end anyway? Crazy that you have to do engine work on a brand new “expensive” 2-stroke.
I'm not sure, and to be honest I hesitated posting this as I'm not sure exactly how much wear is normal for a 2 stroke motor and didn't want to set off a false alarm. What stood out to me though is that the wear on the con rod is the exact place that appears to be failing in a lot of the pictures above where you can see the rod.
I wonder if the wear is normal and the design of the rod just causes it to fail, or the wear is abnormal and the cut-out just causes it to fail faster?
All the 250/300 that have that huge cutout slot are the same bikes that KTM specs at 60:1. I have a suspicion there's a relation there. Running such a low amount of oil they are trying to get max oil to the wrist pin bearing. I'm doing the same as jg791 - ProX rod and 40:1.
Obviously you need a new rod ($150sh). That rod will fail. However, it might be just as easy to get an entire crank (hot rod crank $450ish) for the price of having a new rod installed, especially if you do it yourself.
https://www.revzilla.com/dirt-bike/hot-rods-crankshaft-ktm-husqvarna-ga…
From looking at other photos, it looks to me that the rod was ground that way during manufacturing. That is if I'm understanding what part you think was ground off during operation.
Stock KTM cranks are very good. A stock crank rebuilt with a good rod is a better option than a Hot Rods crank. Getting it rebuilt by a good builder also ensures it will be trued very well, which an out of the box Hot Rods crank might not be. Money wise, rebuilding might still come out cheaper than a complete Hot Rods crank, if you have a good guy local and don't have to pay shipping.
Cool 👍
Look where the rod broke
Yeah I was referring to the material worn off at the small end surface, not the cut-out in the middle (which is confirmed to be a change KTM made to the rods) - not sure if that's what you meant?
Ohhh. I was thinking you meant the cut out part or the circle itself.
Even so, a new rod will most likely fix the (potential) problem 😎
No worries, and that seems to be the general consensus here and with the shops I've talked to. Absolutely bonkers a new bike needs this as a precautionary measure - I've emailed GasGas corporate for their take on it, so we'll see where that goes.
Yeah, that's how they're made. They've ground off the small end, maybe for clearance inside the piston.
That slot cut in the end looks like is the problem to me. Not sure why they felt they needed that.
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